[UPDATE 2:30 p.m.] U.S. Rep. Rush Holt became the first Democrat to officially enter the New Jersey Senate race Thursday.

In an email to supporters, the Central Jersey congressman said, according to the Associated Press, "The reason is simple. I believe I am the best candidate to continue the passionate advocacy for progressive values that Sen. Lautenberg exemplified."

Holt, 64, was assistant director of the Princeton Plasma Physics Laboratory before being elected to Congress in 1998. Around his district, it's not uncommon to see a bumper sticker that proclaims, accurately: "My congressman IS a rocket scientist."

Holt is considered one of the most liberal members of the New Jersey congressional delegation and has pushed for laws against racial profiling and has been critical of drilling for oil and natural gas on public lands and waters, the AP reports.

Fellow Rep. Frank Pallone, D-N.J., and Newark Mayor Cory Booker had already expressed interest in running for the seat in 2014 before Lautenberg died. Since this is a special election, Holt and Pallone will not have to give up their House seast to run.

Only Steve Lonegan, a conservative perennial candidate, has announced for the Republican nomination. New Jersey has not elected a Republican to the U.S. Senate since 1972.

[UPDATE 2:25 p.m.] Chiesa and Christie have been friends and colleagues for two decades, The Star-Ledger of Newark reports. They were law partners in the 1990s, and Chiesa became a top trusted aide when Chistie became U.S. attorney for New Jersey in 2002.

When Christie was elected governor in 2009, Chiesa headed his transition team and became his chief counsel before being named attorney general.

[UPDATE 2:02] Chiesa: “I am not running for the seat. That will not change. … I’m a conservative Republican [but] I’ve got a limited time period to contribute. … I won’t go down there with an armful of draft bills.”

[UPDATE 1:52 p.m.] New Jersey Gov. Chris Christie on the cost of holding a special primary to select Lautenberg’s replacement in October instead of during the usual election cycle: “I don’t believe that siding on letting people select their senator … is something that should be discounted. We’re talking about maybe an additional $12 million in cost.”

New Jersey Gov. Chris Christie announced Thursday that he has selected New Jersey Attorney General Jeffrey Chiesa to fill the seat made empty by the death of Sen. Frank Lautenberg, D-N.J., effective next Monday.

“I’ll use my best judgment and skill that I have to conduct myself in a way to make the people of New Jersey proud,” Chiesa told a press conference Thursday afternoon in Trenton. The attorney general will not run in the Oct. 16 election to select a replacement for Lautenberg, New Jersey's longest-serving senator ever, who died Monday morning at age 89.